The CR-160-R7 is an 'evaluation board' for the CR-200-XX series of Gaussian shaping amplifier modules. The CR-160-R7 makes it easy for the casual experimenter to use the CR-200-XX, providing BNC connectors for input and output, a power supply terminal block, and a socket for the insertion of the CR-200-XX shaping amplifier modules. To provide flexibility in the implementation of the CR-160-R7 within the users' instrumentation, the connectors have been provided unassembled to the CR-160-R7 board.
The CR-160-R7 also includes an adjustable low-noise wide-band amplifier having gains adjustable from 0 to 100. Combined with the CR-200-XX gain of 10, this allows an overall gain of 0 to 1000. Furthermore, an inverted-polarity signal is available, as well as adjustments for pole-zero correction and DC offset.
The CR-160-R7 also includes a socket for the optional use of the CR-210 baseline restoration module. The CR-160-R7 board has dimensions: 3.7 inches x 2.3 inches
The fine gain of the on-board amplifier can be continuously adjusted using a small potentiometer placed between the input and output connectors (see diagram to the right). The coarse gain may be adjusted by implementing one, both, or neither of the two separate amplification stages, each of which has a gain of 10 when 'on' (down). When 'off' (up), the gain of the stage is 1. Keep in mind that, in addition to the gain of the amplifiers on the CR-160-R7 evaluation board, the CR-200-XX shaping amplifier module itself has a gain of 10, resulting in an overall gain to the input signal of anything in the range of 0 to 1000.
Installing the CR-200-XX and CR-210 Modules
Make sure that any module installed on the CR-160-R7 board is installed in correct direction! Installing the modules in the opposite direction will result in damage. Connect pin 1 of the modules (marked with a white dot on the label) to the side of the socket marked "1".
The DC offset of the output can be adjusted using the potentiometer which can be located using the diagram on the right.
Signal polarity can be changed using one of the ‘piano style’ switches located between the input and output connectors. See the diagram for the precise location. Switch position of ‘on’ (down) inverts the signal from the input. If the CR-210 baseline restoration module is being used, the CR-160-R7 output pulses must be positive for the baseline restoration circuit to operate properly. The polarity switch should be used in this case to insure that the output pulse polarity is in fact positive.
Application of Power
The CR-160-R7 requires positive and negative DC power in order to operate. The supply voltage must be in the range from +/- 7 volts to +/- 13 volts. At +/- 12 volts the current draw is 40 mA on both the positive and negative power supplies. This figure includes the current drawn by the installed CR-200-XX module and CR-210 module. If the CR-210 module is not installed, the overall current draw is reduced to 25 mA on the positive and negative supplies.
The output of the CR-160-R7 can swing to up to +9V in the unloaded state, assuming the supply voltages are +/-12V. Generally, the maximum output is 3V less than the supply voltage. Maximum output current is 100 mA. Output impedance is 2 ohms.
Jumper Regarding Optional Use of the CR-210
The CR-160-R7 board is normally set to be used with both a CR-200-XX shaping amplifier module and a CR-210 baseline restoration module installed. If for some reason the user does not want to use baseline restoration, the CR-210 module may be omitted. If omitted, however, the user should add a wire jumper at the location shown in the figure. This jumper effectively shunts the CR-210 circuit.
Set-up of the CR-160-R7 board requires the user to be able to (and preferably be comfortable with) soldering and connecting wires, cables, and connectors to PC boards.